Living with this person sounds miserable, and obviously they're in the wrong for everything, but it's still not cool to go through someone's wallet just because they leave it out just to check their ID.
Yeah, I've had bad roommates before but my reaction has always been to avoid them and want less to do with them, not invade their privacy and find out more about them. I guess that doesn't make for as interesting social media posts [edit: or advertisements] though.